Patient-Specific Pelvic Implants For Acetabular Reconstruction

ABSTRACT

A pelvic implant includes a first surface including a recess configured for receiving a portion of a flange of an acetabular cage and a patient-specific second surface opposite to the first surface. The patient-specific second surface is preoperatively configured from a three-dimensional digital image of a pelvis of a patient to mate and closely conform to a corresponding surface of the pelvis under the flange in only one position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/197,851 filed on Aug. 4, 2011, now U.S. Pat. No. ______. The entiredisclosure of the above application is incorporated herein by reference.

INTRODUCTION

The present teachings provide various patient-specific pelvic implants.The patient-specific pelvic implants can be spacers for revisionacetabular implants used in acetabular reconstruction surgery, such as,for example, protrusio cages or acetabular cages that include anacetabular cup and one or more flanges coupled to the acetabular cup.The patient-specific spacers are prepared preoperatively for thespecific patient based on medical scans of the relevant pelvic anatomyof the patient and are configured to be positioned under the flanges ofthe revision acetabular implants and register and mate with thecorresponding pelvic anatomy of the patient in only one position.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

The present teachings provide a pelvic implant that includes a firstsurface and a patient-specific second surface opposite to the firstsurface. The first surface has a recess configured for receiving aportion of a flange of an acetabular cage. The patient-specific secondsurface is preoperatively configured from a three-dimensional digitalimage of a pelvis of a patient to mate and closely conform to acorresponding surface of the pelvis under the flange in only oneposition.

In some embodiments, the pelvic implant includes an acetabular cagehaving a flange and a patient-specific spacer. The patient-specificspacer has a first surface with a recess configured to receive a portionof the flange and a second surface opposite to the first surface. Thesecond surface is patient-specific and preoperatively configured from athree-dimensional digital image of a pelvis of a patient to mate andclosely conform as a negative to a corresponding surface of the pelvisunder the flange in only one position.

The present teachings also provide a pelvic implant that includes anacetabular cage implantable into a pelvis of a patient and a pluralityof patient-specific spacers. The acetabular cage includes an acetabularcup and a plurality of flanges coupled to the acetabular cup. Eachspacer has a recess receiving a portion of a corresponding flange of theplurality of flanges and a patient-specific surface. Thepatient-specific surface is preoperatively configured from athree-dimensional digital image of the pelvis of the patient to mate andclosely conform to a corresponding surface of the pelvis under theflange in only one position.

In some embodiments, the pelvic implant can include an acetabular cupand a patient-specific flange modularly coupled to the acetabular cup.The patient-specific flange has a patient-specific surfacepreoperatively configured from a three-dimensional digital image of thepelvis of the patient to mate and closely conform as a negative to acorresponding surface of the pelvis under the flange in only oneposition.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a perspective view of a pelvis of a patient;

FIG. 2 is a perspective view of an exemplary acetabular cage;

FIGS. 3A-3C are perspective views of patient-specific spacers for theacetabular cage of FIG. 2 according to the present teachings;

FIGS. 4A-4C are additional perspective views of the patient-specificspacers of FIGS. 3A-3C;

FIGS. 5-7 are different environmental perspective views of the spacersof FIGS. 3A-3C shown with the acetabular cage of FIG. 2 according to thepresent teachings;

FIG. 8 is a perspective view of another exemplary acetabular cage shownwith patient-specific spacers according to the present teachings;

FIG. 9 is an environmental perspective view of the patient-specificspacers shown with the acetabular cage of FIG. 8 according to thepresent teachings; and

FIG. 10 is an exploded perspective view of an acetabular cup with apatient-specific flange according to the present teachings.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Exemplary embodiments will now be described more fully with reference tothe accompanying drawings.

The present teachings generally provide patient-specific pelvicimplants. The pelvic implants include patient-specific spacers forrevision acetabular implants used in acetabular reconstruction surgery,including, for example, acetabular cages having acetabular cups withflanges or protrusio cages. The patient-specific spacers are preparedpreoperatively for the specific patient based on medical scans of therelevant pelvic anatomy of the patient and positioned under the flangesof the revision acetabular implants.

Generally, patient-specific devices including implants and/orpatient-specific instruments can be designed preoperatively usingcomputer-assisted image methods based on three-dimensional images of thepatient's joint anatomy reconstructed from MRI, CT, ultrasound, X-ray,or other medical scans of the patient's anatomy. Various CAD programsand/or software can be utilized for three-dimensional imagereconstruction, such as, for example, software commercially available byMaterialise USA, Plymouth, Mich.

Various pre-operative planning procedures are disclosed in commonlyassigned and co-pending U.S. patent application Ser. No. 11/756,057,filed May 31, 2007, U.S. patent application Ser. No. 12/103,824, filedApr. 16, 2008; U.S. patent application Ser. No. 12/371,096, filed Feb.13, 2009, U.S. patent application Ser. No. 12/483,807, filed Jun. 12,2009; U.S. patent application Ser. No. 12/872,663, filed Aug. 31, 2010,U.S. patent application Ser. No. 12/973,214, filed Dec. 20, 2010, andU.S. patent application Ser. No. 12/978,069, filed Dec. 23, 2010. Thedisclosures of the above applications are incorporated herein byreference.

In the preoperative planning stage for acetabular reconstruction, apreoperative surgical plan is formulated for a specific patient withinteractive input from the patient's surgeon or other medicalprofessional. Imaging data of the relevant anatomy of a patient can beobtained at a medical facility or doctor's office, using any of themedical imaging methods described above. The imaging data can include,for example, various medical scans of a relevant joint portion or otherrelevant portion of the patient's anatomy, as needed for joint or otheranatomy modeling and, optionally, for determination of an implantalignment axis or for other alignment purposes. The imaging data thusobtained and other associated information can be used to construct athree-dimensional computer (digital) image of the joint or other portionof the anatomy of the patient, such as, in the present application, thepatient's pelvis including the acetabular socket. The three-dimensionaldigital image of the patient's anatomy is used to formulate apreoperative surgical plan for the patient. The preoperative surgicalplan includes the design and construction of implants and/or instrumentsaccording to selected methods of surgical preparation and implantation.

Generally, the patient-specific spacers and/or other patient-specificimplants of the present teachings are configured to match the pelvicanatomy of a specific patient and are generally designed and configuredusing computer modeling based on the patient's reconstructedthree-dimensional digital image of the patient's pelvic anatomy. Thepatient-specific implants have a pelvis engagement surface that isconfigured to conformingly contact and match a corresponding pelvicsurface of the patient (with or without cartilage or other soft tissue),using the reconstructed three-dimensional digital image of the patient'spelvic anatomy and the computer methods discussed above. In thisrespect, a patient-specific implant can register and nestingly mate withthe corresponding bone surface (with or without articular cartilage) ofthe specific patient in only one position.

In reconstructive or revision acetabular surgery, the old acetabularimplant is removed from the pelvic bone or pelvis 80 and the acetabulararea is prepared for a new acetabular implant. Soft tissue may beremoved from the acetabular socket 82, from the acetabular rim 84 andfrom adjacent areas of the ilium 86, ischium 88 and pubic bone 90 (seeFIG. 1). The pelvis 80 can be inspected for defects that will requirethe use of augments and other defect-correcting implants. The acetabularsocket 82 can be reamed in preparation for receiving an acetabular cage(revision acetabular implant) that includes an acetabular cup (or shellor dome) with integral or modular flanges. An exemplary acetabular cage100 is illustrated in FIG. 2. Various acetabular cages similar to theacetabular cage of FIG. 2 are commercially available from BiometManufacturing Corp., Warsaw, Ind. The acetabular cage 100 can include anacetabular cup 102 having a generally semi-spherical shape bounded by acup rim 110.

The acetabular cage 100 is illustrated as having three flanges in thisexemplary embodiment, although a different number of flanges and/orother hook or blade elements can be included. Referring to FIG. 2, firstand second iliac flanges 104, 106 and an ischial flange 108 areillustrated. In this exemplary embodiment, the first iliac flange 104has a first (proximal) portion 105 extending from the cup rim 110 and asecond (distal) portion 107 that is square-like with four fixation holes116 for fixation fasteners 111 (see FIG. 5) arranged to form asubstantially square or square-like shape. The second iliac flange 106has a first (proximal) portion 122 extending from the cup rim 110 and asecond (distal) portion 121 that has an elongated rectangular shape withtwo fixation holes 118 arranged along the elongated rectangular shape.In some embodiments, the first portions 105 and 122 of the first andsecond iliac flanges 104, 106 can be continuous or unitary such that thefirst and second iliac flanges 104, 106 can be in the form of a singlebifurcated iliac flange. The third or ischial flange 108 has a first(proximal) portion 126 extending from the cup rim 110 and a second(distal) portion 123 that has a triangular shape with two fixation holes120. In the illustration of FIG. 2, the fixation holes 120 are orientedalong one side of the second portion 123 and are offset from acenterline of the ischial flange 108. It will be appreciated, however,that the various fixation holes 116, 118, 120, their arrangements on theflanges 104, 106, 108 and the shapes and number of the flanges can varyfor different acetabular cages 100.

The acetabular cup 102 can also include an apical hole 112 for couplingwith an acetabular inserter. Various fixation holes 114 can be providedthrough the acetabular cup 102 for selective use with screws or otherfixation fasteners by the surgeon. Fixation holes 124 for fixationfasteners can also be provided along the first portions 105, 122, 126 ofthe corresponding first, second and third flanges 104, 106, 108. Theconvex bone-engaging surface of the acetabular cup 102 can be coatedwith porous coating, such as a titanium alloy plasma spray porouscoating commercially available from Biomet Manufacturing Corp., Warsaw,Ind.

Referring to FIGS. 3A, 3B and 3C (top side perspective views) and 4A, 4Band 4C (bottom side perspective views), exemplary embodiments of first,second and third patient-specific spacers (or shims) 200A, 200B, 200C(referenced collectively as 200) are illustrated. The patient-specificspacers 200A, 200B, 200C are configured for the first, second and thirdflanges 104, 106,108 and also for the underlying anatomy of the specificpatient, as determined by the three-dimensional digital imagereconstruction of the pelvis of the patient from medical scans of thepatient, as discussed above. More specifically, each patient-specificspacer 200A, 200B, 200C includes first and second opposing surfaces 204and 220, a peripheral surface 202 between the first and second surfaces204, 220 and various fixation holes 210 (or 210A, 210B, 210C)corresponding to the fixation holes of the respective flanges 104, 106,108. The peripheral surface 202 forms an elevated ridge 206, such thatthe ridge 206 and the first surface 204 form a slot or recess 207(collectively for 207A, 207B, 207C) for receiving a second portion of acorresponding flange 104, 106, 108, as discussed below.

Referring to FIGS. 3-7, the recess 207 of each patient-specific spacer200A, 200B, 200C is configured during the preoperative plan to receiveslidably or in a press-fit manner the second or distal portion 107, 121,123 of the corresponding flange 104, 106, 108. In the exemplaryillustrations, the recess 207A of the first spacer (or first iliacspacer) 200A is square-shaped to receive the second portion 107 of thefirst iliac flange 104. Similarly, the recess 207B of the second spacer(or second iliac spacer) 200B is shaped as an elongated rectangle toreceive the second portion 121 of the second iliac flange 106. Therecess 207C of the third spacer (or ischial spacer) 200C is shaped as atriangle to receive the second portion 126 of the ischial (third) flange108.

With continued reference to FIGS. 3-7, the second surface 220 is apatient-specific bone-engaging surface that is configured during thepreoperative plan to register in only one position and mate in acomplementary manner (i.e., as a negative or mirror surface) to theiliac and ischial portions of the pelvis 80 that are under thecorresponding iliac and ischial flanges 104, 106, 108, when theacetabular cage 100 is implanted. As can be seen in FIGS. 5-7, thepatient-specific spacers 200 have a thickness h (i.e., height h ofperipheral surface 202) that is substantially greater than the thicknessof the flanges 104, 106, 108, although the thickness h can be variabledepending on the pre-planned location of the spacer 200 relative to thepelvis 80. For example, in the embodiments of FIGS. 3-7, the first andsecond spacers 200A, 200B are iliac spacers and have a substantiallyvariable thickness h, while the third spacer 200C is an ischial spacerand is shown with a substantially constant thickness. It should beappreciated, however that the thickness h of the spacers is alsodetermined during the preoperative plan according to the anatomy of thespecific patient and the surgeon-selected location for the flanges 104,106, 108. Accordingly, the thickness h can vary in a patient-specificmanner. Accordingly, the spacers 200 can provide reinforcement for thecorresponding flanges 104, 106, 108. Further, the flanges 104, 106, 108themselves can be configured with greater thickness and rigidity,because using their patient-specific spacers 200 makes it unnecessary tomake the flanges 104, 106, 108 bend to engage the patient's pelvis 80.The acetabular cage 100 itself, including the location, number and shapeof the various iliac and ischial flanges (such as flanges 104, 106, 108)in combination with the corresponding patient specific spacers 200 canbe determined and selected during the preoperative plan based on thepatient's anatomy and with surgeon input.

Computer instructions of tool paths for machining the patient-specificspacers 200 can be generated and stored in a tool path data file. Thetool path can be provided as input to a CNC mill or other automatedmachining system, and the patient-specific spacers 200 can be machinedfrom solid or porous metals and/or alloys. The patient-specific spacers200 can also be manufactured from powder metal using rapid prototypingmethods, such as, for example, stereolithography, laser depositionsintering or other such methods. The patient-specific spacers 200 can besterilized and shipped to the surgeon or medical facility for use duringthe surgical procedure in a patient and surgeon specific kit. Inaddition to the patient-specific spacers 200, the kit can include theacetabular cage 100, an acetabular cup liner or other articulatingbearing for the femoral head (not shown), various fixation screws andfasteners, various non-custom or patient-specific augments for theacetabular cup (dome) 102, as well as a selection of instrumentsgenerally used for the surgical procedure or specifically requested bythe surgeon. The instruments in the kit can include an acetabular cupinserter and/or impactor, a reamer, various flange benders, vise gripinstruments and other instruments for the surgical procedure, such asthose commercially available from Biomet Manufacturing Corp., Warsaw,Ind. Patient-specific augments for the dome of the acetabular cup 102are described in commonly assigned U.S. patent application Ser. No.12/978,069, filed Dec. 23, 2010, the disclosure of which is incorporatedherein by reference.

Referring to FIGS. 8 and 9, patient-specific spacers 400 can besimilarly constructed for another exemplary acetabular cage 300 that isused in acetabular reconstruction. Acetabular cages similar toacetabular cage 300 are commercially available Biomet ManufacturingCorp., Warsaw, Ind. The acetabular cage 300 can include an acetabularcup or shell 302 having a cup rim 310, an ischial blade 330 extendingfrom a first outer slot 312 of the acetabular cup 302, an obturatorforamen hook 332 extending from a second outer slot 312 of theacetabular cup 302 and a bifurcated iliac flange 333 that includes acommon first (proximal) portion 334 extending from the cup rim 310 andfirst and second distal flange portions 336, 338 extending from thecommon first portion 334. In this embodiment of the acetabular cage 300,the ischial blade 330, the obturator foramen hook 332 and the bifurcatediliac flange 333 are removably coupled to the acetabular cup 302 bysnap-fit and/or by using, for example, screws or other fasteners and areselectively included in the prosthesis at the discretion of the surgeon.For example, in the environmental view of FIG. 9 only the bifurcatediliac flange 333 and the obturator foramen hook 332 are shown. Anexemplary fastener 342 coupling the obturator foramen hook 332 to theacetabular cup 302 is shown in the view of FIG. 8 and a similar fastenercan be used for the ischial blade 330 (hidden from view). The firstportion 334 of the bifurcated iliac flange 333 can also be attached withfasteners to a corresponding extension 309 of the cup rim 310.

The acetabular cup 302 and the ischial blade 330 can be made from atitanium alloy (such as Ti-6Al-4V, for example). The convex(bone-engaging surface of the acetabular cup 302 can be coated withporous coating, such as a titanium alloy plasma spray porous coatingcommercially available from Biomet Manufacturing Corp., Warsaw, Ind. Theobturator foramen hook 332 and the bifurcated iliac flange 333 can bemade from pure titanium or other metal. The obturator foramen hook 332can be crimped by the surgeon during implantation. The bifurcated iliacflange 333 can also be bent during implantation. In other embodiments,the bifurcated iliac flange 333 can also be made of titanium alloy andhave a greater thickness when used with the patient-specific spacers 400because, as discussed above in connection with the spacers 200, eachpatient-specific spacer 400 is also designed preoperatively to registerin only one position and nestingly mate (as a negative) with theunderlying iliac surface of the specific patient and provide rigidityand support on the corresponding iliac surface without the need to bendthe iliac flange 333. Apart from the fact that the spacers 400 aredesigned to receive the corresponding first and second distal flangeportions 336, 338 of the bifurcated iliac flange 333, the spacers 400are similar to the spacers 200 and the description of similar featuresis not repeated. For example, each patient-specific spacer 400 has arecess 407 that receives a corresponding distal iliac flange portion336, 338 and an opposite patient-specific surface 420 configured duringthe preoperative plan to mate to a corresponding iliac anatomy of thepelvis 80 of the patient and register in only one position.

In some embodiments, an entire flange can be preoperatively designed tobe patient-specific to nestingly conform to the specific patient'speriacetabular anatomy in a single position, without the need ofintraoperative bending or other deformation by the surgeon. In thisrespect, the patient-specific flange can be designed with adequatethickness for stability and rigidity and without using any spacers. Anexemplary patient-specific flange 500 is illustrated in FIG. 10. Thepatient-specific flange 500 can be modularly or removably connected toan acetabular cup 302 (shown generically). In some embodiments, thepatient-specific flange 500 can have a connecting portion 520 with anopening 502 for receiving a fastener 514 from a corresponding connectingportion 311 of the acetabular cup 311, although other types of modularconnectors can be used, such as tongue-and-groove with or withoutscrews, etc.

The patient-specific flange 500 has first and second opposing surfaces504, 506. The first surface 504 is configured as a patient-specificsurface that mirrors (as a negative surface) the corresponding pelvicanatomy of the patient. Accordingly, the width or thickness “t” of theflange between the first and second surfaces 540, 506 can be variable ina patient-specific manner. The patient-specific flange 500 is showngenerically with two fixation holes 510, although it will be appreciatedthat the patient-specific flange 500 can be designed with differentnumber of and arrangement of fixation holes and overall shape. Themodular patient-specific flange 500 can be used in an acetabular cage(100, 300) that includes additional non custom flanges andpatient-specific spacers (200, 400) for the non-custom flanges, asdescribed above. In this respect, the patient-specific flange 500 canreplace one of the non-custom flanges of the acetabular cage

Summarizing, the present teachings provide various patient-specificspacers 200, 400 that can be included in a kit for acetabular revisionsurgery for a specific patient. The patient-specific spacers 200, 400are designed during a preoperative surgical plan of the patient based ona three dimensional digital image of the pelvic anatomy of the patientthat is constructed using commercially available software from medicalscans of the patient. The design and construction of thepatient-specific spacers 200, 400 are made preoperatively in conjunctionand coordination with the selection of an appropriate acetabular cagefor the patient. A plurality of patient-specific spacers 200, 400 can beincluded in the kit. The patient-specific spacers 200, 400 combinepatient-specific customization with rigidity and reinforcement for theflanges of the acetabular cage and can relieve the surgeon from the needto bend corresponding flanges of the acetabular cages intraoperativelyfor engagement with the pelvis of the specific patient. In this respect,the patient-specific spacers can facilitate and possibly streamline someacetabular reconstruction procedures. In some embodiments, modularpatient-specific flanges for use without spacers can also be included inthe kit.

Example embodiments are provided so that this disclosure is thorough,and fully conveys the scope to those who are skilled in the art.Numerous specific details are set forth such as examples of specificcomponents, devices, and methods, to provide a thorough understanding ofembodiments of the present disclosure.

It will be apparent to those skilled in the art that specific detailsneed not be employed, that example embodiments may be embodied in manydifferent forms and that neither should be construed to limit the scopeof the disclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail. Accordingly, individual elements or features of aparticular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. A pelvic implant system comprising: an acetabularcage implantable into a pelvis of a patient; the acetabular cageincluding an acetabular cup and a plurality of flanges coupled to anupper portion of the acetabular cup; and a plurality of spacers, whereineach spacer comprises first and second opposing surfaces, a peripheralsurface located between and to space apart the first and secondsurfaces, wherein the first surface has a recess configured to receive acomplementary-shaped portion of a corresponding flange of at least oneflange of the plurality of flanges, wherein the second surface defines apatient-specific bone-engaging surface preoperatively configured tocomplementary mate and closely conform to a surface of the pelvis underthe flange in one position, wherein at least one flange of the pluralityof flanges includes an iliac flange and at least one spacer of theplurality of spacers includes an iliac spacer couplable to said iliacflange.
 2. The pelvic implant system of claim 1, wherein the peripheralsurface includes a ridge surrounding the recess that is elevatedrelative to the first surface,
 3. The pelvic implant system of claim 2,wherein the patient-specific bone-engaging surface is preoperativelyconfigured to complementary mate and closely conform to a surface of thepelvis under the flange in only one position.
 4. The pelvic implantsystem of claim 3, wherein the patient-specific bone-engaging surface ispreoperatively configured from a three-dimensional digital image of thepelvis.
 5. The pelvic implant system of claim 3, wherein at least theiliac flange includes a substantially square shape or square-like shape.6. The pelvic implant system of claim 5, wherein the recess of the iliacspacer has an elongated rectangular shape.
 7. The pelvic implant systemof claim 5, wherein the recess of the iliac spacer has a square shape.8. The pelvic implant system of claim 4, wherein another flange of theplurality of flanges is an ischial flange and the patient-specificspacer is an ischial spacer, wherein the recess of the ischial spacerhas a triangular shape.
 9. The pelvic implant system of claim 1, whereinat least one flange of the plurality of flanges is removably coupled tothe acetabular cup.
 10. The pelvic implant system of claim 9, whereinthe at least one flange of the plurality of flanges that is removablycoupled to the acetabular cup is an ischial blade modularly coupled tothe acetabular cup.
 11. The pelvic implant system of claim 1, furthercomprising: an obturator foramen hook modularly coupled to theacetabular cup.
 12. The pelvic implant system of claim 1, wherein theiliac spacer includes a plurality of iliac spacers, wherein each iliacspacer of the plurality of iliac spacers includes a height differentfrom the other iliac spacers such that the plurality of iliac spacershas a variable height.
 13. A pelvic implant system comprising: apatient-specific spacer having a first surface with a recess configuredfor receiving at least a portion of a flange of an acetabular cage,wherein the acetabular cage is configured to be placed in an acetabularsocket of a pelvis; and wherein the patient-specific spacer has apatient-specific second surface opposite to and spaced apart from thefirst surface, the patient-specific second surface preoperativelyconfigured from a three-dimensional digital image of the pelvis to mateand closely conform to a surface of the pelvis under the flange in onlyone position on the pelvis.
 14. The pelvic implant system of claim 13,wherein the patient-specific spacer includes a plurality of patientspecific spacers, wherein each of the patient-specific spacers includesa peripheral surface has a height; wherein the height of eachpatient-specific spacer is different from each of the otherpatient-specific spacers, such that the plurality of patient-specificspacers has a variable height.
 15. The pelvic implant system of claim13, wherein the recess is at least one of triangle-shaped, elongatedrectangle-shaped, substantially square-shaped, or square-shaped.
 16. Thepelvic implant system of claim 15, wherein the recess is configured forat least one of an ischial flange or an iliac flange.
 17. A pelvicimplant system comprising: an acetabular cage implantable into a pelvisof a patient; the acetabular cage including an acetabular cup and aplurality of flanges coupled to the acetabular cup; and a plurality ofpatient-specific spacers, wherein each spacer has an elevated ridge thatare least partially surrounds a recess surface that is recessed relativeto an upper edge of the elevated ridge for receiving a portion of onecorresponding flange of the plurality of flanges, wherein each patientspecific spacer further has a patient-specific surface that is designedand preoperatively configured based on a three-dimensional digital imageof at least a portion of the pelvis of the patient to mate and closelyconform to a corresponding surface of the pelvis under one flange of theplurality of flanges in only one position; wherein at least one flangeof the plurality of flanges, at least one spacer of the plurality ofspacers, or a combination thereof is designed and preoperativelyconfigured based on the of the three-dimensional digital image of atleast the portion of the pelvis of the patient to mate and closelyconform to the corresponding surface of the pelvis under the flange inonly one position.
 18. The pelvic implant system of claim 17, wherein atleast one flange of the plurality of flange is a patient-specific flangemodularly coupled to the acetabular cup and having a patient-specificsurface preoperatively configured from a three-dimensional digital imageof the pelvis of the patient to mate and closely conform as a negativeto a corresponding surface of the pelvis under the flange in only oneposition.
 19. The pelvic implant system of claim 17, wherein at leastone flange is removably coupled to the acetabular cup.
 20. The pelvicimplant system of claim 17, wherein the plurality of flanges includes aniliac flange and an ischial flange; wherein the plurality ofpatient-specific spacers includes an iliac spacer and an ischial spacer.21. The pelvic implant system of claim 17, wherein each patient-specificspacer of the plurality of patient-specific spacers includes adifferently shaped perimeter.
 22. The pelvic implant system of claim 17,wherein each patient-specific spacer of the plurality ofpatient-specific spacers includes a different height.